1Heat oven to 325°F. Spray 9-inch glass pie plate with cooking spray. In small bowl, mix cracker crumbs and 1/4 cup melted butter; press evenly in bottom and up side of pie plate.
2In 10-inch skillet, melt 2 tablespoons butter over medium-high heat. Cook onions in butter 5 to 6 minutes, stirring frequently, until light brown. Spread onions in crust. Sprinkle with cheese.
3In medium bowl, beat milk, salt, pepper and eggs with fork or wire whisk until blended; pour over cheese.
4Bake 40 to 45 minutes or until knife inserted in center comes out clean. Garnish with tomato and onion. Serve immediately.